A Theory of general causes of violent crime: Homicides, income inequality and deficiencies of the heat hypothesis and of the model of CLASH

This paper has two goals. The first is to show that the heat hypothesis provides a partial explanation of violent crime in society. The second is to suggest an alternative hypothesis that intentional homicides can be explained by the level of income inequality, even when controlling thermal climate and other factors. The vast literature in these research fields has suggested several approaches to explain aggression and violent behavior in society, such as the heat hypothesis and the model of Climate, Aggression, and Self-control in Humans (CLASH). However, there are at least some factors about aggression and violent behavior that current theories have trouble explaining. This study proposes income inequality, latitude and their interaction as predictors of intentional homicides. Statistical evidence based on country-level analyses (N =191 countries) reveals that controlling thermal climate and other factors, socioeconomic inequality is positively associated with violent crime. In particular, the findings here seem in general to support the hypothesis that differences between countries in intentional homicides (per 100,000 people) can be explained by the level of income inequality alone, and not thermal climate as a second predictor or the interaction of income inequality and thermal climate. These results suggest that income inequality may overpower the role of hot weather and seasonal variation of temperature to explain the level of violent crime in human society. A prediction of this theory here is that societies with low socioeconomic inequality, independently of thermal climate, are not likely to produce high levels of intentional homicides and violent crime. This finding can be useful for bringing a new perspective to explain and generalize one of the determinants that generates violent crime in human society. Some policy implications are suggested to reduce these social issues.